This invention relates to display devices and in particular to a visual effect device utilizing a sealed narrow chamber and the movement of a liquid of one specific gravity with respect to a liquid of a second specific gravity within the chamber.
The present invention belongs to a category of devices which utilize visual effects produced when two contrastingly colored liquids, immiscible in one another, are placed in a container and subjected to physical action such as heating, shaking, change of orientation and the like.
One example is a device known under the commerical name "Lava Lamp." this case two contrastingly colored, immiscible liquids are contained in a bottle-like chamber with a heat source located in the base. The heat from the source causes one of the two liquids to in an effect "boil," producing a slow but observable upward flow of large globules of the one liquid relative to the other. Upon moving away from the heat source, the globules cool and tend to settle toward the heat source. Thermal currents in the liquids produce an ever changing geometry of the globules. Light directed through the bottle-like chamber enhances the visual effect produced. When the globules settle they are again reheated and the process repeats itself producing a continuously changing display until the heat is removed.
Other devices utilize the influence of gravity to produce visual effects. One such device is of the type described in U.S. Pat. No. 3,564,740 in which a multi-compartment display device is provided with liquids of different specific gravities stored therein. The visual effect produced by the relative movement of the liquids is obtained by inverting the device like an hour glass to produce the gravity flow of the heavier liquid in the downward direction with the consequent upward displacement of a lighter liquid. The flow of liquids is accomplished by a valving or porting arrangement in barriers or partitions which divide the several compartments of the display device, one from the other.
The relative flow of liquids of different specific gravities akin to that utilized in the Calfee U.S. Pat. No. 3,564,740 is utilized by the present invention, but with several important differences. In the first instance the beading or droplet forming action is provided by the liquids themselves as the heavier liquid flows around baffles and obstructions in its flow path without the use of ports or valves of any kind. In addition, beacuse the invention utilizes a pair of plates defining a narrow chamber for the liquids, the color contrast and visual effect is maximized because each of the liquids abuts the inside surfaces of the plates and are viewed directly through the plates. In Calfee one liquid flows through the other interiorly of the container walls and the view thereof is obscured to the extent that the line of sight to the drops of the first liquid passes through said other liquid.
The present invention eliminates the use of special ports or valves single or in symmetrical pairs and utilizes a reservoir at one end and a main chamber. A simple opening or aperture in the barrier defining the boundary between reservior and main chamber provides the means for communicating liquids between reservoir and chamber. Each aperture in combination with an associated baffle in turn provides the means for splitting the flow from the reservoir into a multiplicity of slow paths extending from top to bottom of the display device, adding immeasurably to the dynamic visual effect produced. Finally, the present invention is a substantial improvement over the Calfee device in providing liquid combinations utilizing liquids other than water in that it has been found that formulations of water and oil as prescribed by Calfee will not produce the droplet or beading effect characteristic of the present invention without special ports or valves.